This invention relates to backflow and back-siphonage preventers, in particular for use on high pressure plumbing supply lines.
High pressure hose drops, e.g. operating at pressures of up to 400 psi, are often used for the washdown of equipment and facilities, such as in food processing plants. It is recognized that it is desirable to protect a plumbing supply line providing water to hose drop stations against contamination by reverse flow through the hose (i.e. backflow and/or back-siphonage) of potentially contaminated water from the processing and rendering areas into the potable water supply.
According to the invention, a high pressure hose drop is equipped with a backflow and back-siphonage preventer assembly consisting of a ball valve and a double check valve backflow preventer with an atmospheric vent. The backflow and back-siphonage preventer assembly of the invention is particularly suited for isolation protection on high pressure plumbing supply lines, such as high pressure hose drops used for the washdown of equipment and facilities, e.g. in food processing plants.
According to one aspect of the invention, a backflow preventer includes a housing defining a fluid flow channel, an inlet at an upstream region of the housing in fluid communication with the fluid flow channel, an outlet at a downstream region of the housing in fluid communication with the fluid flow channel, and a drain outlet passage between the upstream region and the downstream region. A first valve is located upstream of the drain outlet passage for controlling fluid flow in the fluid flow channel, and a second valve is located downstream of the drain outlet passage for controlling fluid flow in the fluid flow channel. The backflow preventer includes a sealing member configured to move between a first position in which the drain outlet passage is closed to limit fluid communication between the drain outlet passage and the fluid flow channel, and a second position in which the drain outlet passage is open to permit fluid communication between the drain outlet passage and the fluid flow channel. A reinforcing member is operatively coupled to the sealing member to permits operating pressures of greater than about 500 psi without blow-out of the sealing member.
Embodiments of this aspect of the invention may include one or more of the following features. The sealing member is biased toward the first position in the absence of backflow in the fluid flow channel. The first valve includes a valve member. The valve member is moved out of engagement with the sealing member during normal flow. The valve member is biased toward a position in engagement with the sealing member by, for example, a spring.
In the illustrated embodiment, the valve member is biased toward a closed position against a seat. The reinforcing member is biased toward the first position. The sealing member provides the seat and a biasing force for biasing the reinforcing member toward the first position.
The reinforcing member is configured to move between a first position in which the drain outlet passage is closed to limit fluid communication between the drain outlet passage and the fluid flow channel, and a second position in which the drain outlet passage is open to permit fluid communication between the drain outlet passage and the fluid flow channel. The sealing member and the reinforcing member are coupled such that movement of the sealing member during backflow conditions allows the reinforcing member to move toward its second position. The reinforcing member is biased toward its second position by, for example, a spring. The reinforcing member is positioned between the sealing member and the outlet passage.
A ball valve and a strainer are located upstream of the first valve.
According to another aspect of the invention, a valve assembly includes a housing defining a fluid flow channel, an inlet at an upstream region of the housing in fluid communication with the fluid flow channel, an outlet at a downstream region of the housing in fluid communication with the fluid flow channel, and a drain outlet passage between the upstream region and the downstream region. A valve is located upstream of the drain outlet passage for controlling fluid flow in the fluid flow channel. The valve assembly includes a sealing member configured to move between a first position in which the drain outlet passage is closed to limit fluid communication between the drain outlet passage and the fluid flow channel, and a second position in which the drain outlet passage is open to permit fluid communication between the drain outlet passage and the fluid flow channel. A reinforcing member is operatively coupled to the sealing member to permit operating pressures of greater than about 500 psi without blow-out of the sealing member.
The backflow and back-siphonage preventer assembly of the invention advantageously provides protection against back-siphonage and back-pressure backflow to resist reverse flow of potentially contaminated water from the processing and rendering areas into the potable water supply. The backflow preventer safeguards the water supply, thus ensuring that the water is safe to drink and safe for use in processing meat within the facility.
The assembly is also advantageously designed for non-health hazard applications, and for use where continuous pressure conditions exist. For this purpose, the assembly advantageously incorporates a bronze ball valve shutoff on the inlet of the assembly and incorporates, on the outlet of the assembly, a dual check with atmospheric vent specifically designed to handle temperature and pressure conditions commonly found in the meat processing industry.
Other features and advantages will be apparent from the following description of a presently preferred embodiment.